In a 1 L single neck round bottom flask equipped with a magnetic stirrer and a reflux condenser, ethyl (2E,4E)-5-(dimethylamino)-2-(2,2,2-trifluoroacetyl)penta-2,4-dienoate (80.50 g, 303.8 mmol) was dissolved in a solvent mixture of methanol (700 mL) and 25% aqueous ammonia solution (240 mL). The reaction mixture was heated to 70 °C and maintained for 20 minutes. It was then cooled to room temperature and the methanol was removed by distillation under reduced pressure. The residue was diluted with water (200 mL) and extracted with ether (2 x 300 mL). The organic phases were combined, washed with saturated brine (200 mL), dried over anhydrous magnesium sulfate and filtered. The solvent was evaporated under reduced pressure to give 65.0 g of red oily crude product. The crude product was pure enough for subsequent reactions. For further purification, the crude product was filtered through a short silica gel column, followed by evaporation of the filtrate to give 59.9 g of light yellow flowing oil in 90% yield.
